Modification of prolamins with glycols



Patented Mar. 20, 1951 MODIFICATION OF PROLAMINS WITH GLYCOLS John 'P.Dunne, New York, N. Y., assignor to Columbian Carbon Company, New York,N. Y., a corporation of Delaware No Drawing. Original application July19, 1947, Serial No. 762,211. Divided and this application Augnst 17,1949, Serial No. 110,896

7 Claims. (01. 260-123) This invention relates to a method for theproduction of modified prolamins which are characterized by increasedmiscibility with water and other desirable properties.

It is known in the art to prepare solutions of prolamins (e. g., zein),the prolamins being dissolved in aqueous ethanol, or in glycols orpolyglycols. Such solutions have little or no tolerance for water, andthe addition of sufficient water thereto causes precipitation of thepro-, lamin. Prolamin emulsions or dispersions in water have alsobeenmade using soaps, particularly rosin soaps, sulfated oils, etc.However,

such emulsions or dispersions may be prepared only in low solidscontent. Furthermore, such emulsions or dispersions are of limitedstability.

It is therefore an object of this invention to provide a method for themodification of a prolamin to provide a product of increased miscibi1-ity with water.

It is another object of this invention to provide a method for theproduction of a modified prolamin which is infinitely miscible withwater.

It is also an object of this invention to provide a method for theproduction of a modified zein which is infinitely miscible with water.

It is a further object of this invention to pro vide a method for themodification of a prolamin, particularly zein, to form a product whichis in-- finitely miscible with water and which may be incorporated intowater to form stable solutions which are not affected by air, light orthe normal temperatures of storage.

The foregoing and other objects are accomplished in accordance with thepresent invention by heating a prolamin in contact with a mixturecontaining certain glycols or polyglycols and a strong alkali.

For a more complete understanding of the present invention, reference ismade to the following example, which is to be considered not limitativeof the invention.

Example 712 gms. of propylene glycol was charged to a reaction flaskequipped with a reflux condenser, and 80 gms. of zein and 8 gms. of drysodium hydroxide were mixed therein. The temperature of the reactionmixture was then raised to 110 0., and held at that temperature forone-half hour. At this point, a sample of the reaction mixture could bediluted with up to about an equal weight of water at room temperaturewithout precipitating zein from the solution. After the reaction mixturehad been heated for an additional one-half hour at the same temperature,it

2 was miscible with water in all proportions at room temperature, andaqueous solutions thereof were stable over an extended period of time.

The foregoing example illustrates the method of the present inventionfor the modification of a prolamin to render it more completely miscibleWith water by heating the prolamin in a mixture with a glycol orpolyglycol and a strong alkali. In the example zein was the specificprolamin which was modified. However, for zein there may be substitutedin the example any other prolamin, such as gliadin, hordein or kafarin,or mixtures of the aforementioned prolamins.

Furthermore, in place of the propylene glycol employed in the example,there may be substituted any other glycol or polyglycol which isinfinitely miscible with water at 20 C. (e. g., ethylene glycol,trimethylene glycol, diethylene glycol, dipropylene glycol, triethyleneglycol, tetraethylene glycol, tripropylene glycol. Polyethylene Glycol200 (a proprietary mixture of polyethylene glycols having an everagemolecular weight of -210), Polyethylene Glycol 400 (a proprietarymixture of polyethylene glycols having an average molecular weight of380-420 and a freezing range of 4-10 0.), Polyethylene Glycol 600 (aproprietary mixture of polyethylene glycols having an average molecularweight of 570- 630 and a freezing range of 20-25 C.), etc., orpolyethylene glycol which is not infinitely miscible with water at 20 C.but which has a molecular weight below about 1600 (e. g., CarbowaxCompound 1000 (a proprietary mixture of polyethylene glycols having anaverage molecular weight of 950-1050 and a freezing range of 35-40 0.),Carbowax Compound 1500 (a proprietary mixture of polyethylene glycolshaving an average molecular weight of 500-600 and a freezing range of35-40 C.) Carbowax Compound 1540 (a proprietary mixture of polyethyleneglycols having an average molecular weight of 1300-1600 and a freezingrange of 40-50 C.), etc.), or mixtures thereof.

The relative proportions of prolamin and glycol or polyglycol may bevaried over a wide range, depending upon the particular prolaminemployed, the particular glycol or polyglycol used, the characteristicsdesired in the reaction prodnot, etc. Thus, when propylene glycol andrefined zein are employed, the minimum amount of glycol required isapproximately 1.6 parts by weight per part of zein, if a product whichis completely miscible with water is to result from the reaction.Somewhat greater amounts of glycol and polyglycol of highermolecularweight than propylene glycol are required if the same effect isto be produced. With ethylene glycol a somewhat smaller amount thereofmay be used if a similar result is to be obtained using zein.

As the example illustrates, the modification of the prolamin may beeffected using as a catalyst sodium hydroxide. However, in place of thesodium hydroxide there may be substituted any other strongly alkalinematerial, such as potassium hydroxide, lithium hydroxide,tetramethylammonium hydroxide, etc., or materials which decompose underthe reaction conditions to yield strongly alkaline materials, such assodium acetate, potassium oxalate, sodium citrate, sodium lactate,sodium formate, etc., or mixtures thereof. In general, the reactionmixture should preferably contain from about 2 to about parts ofstrongly basic material per 100 parts of prolamin contained therein.

In the example, the modification of the prolamin was effected by heatingthe reaction mixture at 110 C. for a period of time. A wide range ofreaction temperatures may be employed in practicing the method of thepresent invention, such temperatures generally being in the range fromabout 80 to about 120 C., and preferably from about 100-120 C. Thetemperature of the reaction mixture should not be allowed to risesubstantially above about 120 C., as some decomposition of the .prolaminmay take place at higher temperatures.

The reaction of the prolamin and the glycol or polyglycol may be carriedout in any suitable vessel, such as a jacketed dough mixer, a jacketedkettle preferably equipped with a reflux condenser, etc. The preferredmethod of efiecting the reaction is to add the prolamin and stronglyalkaline material to the glycol or polyglycol while the glycol orpolyglycol is heated and agitated, the addition of the prolamin andstrongly a1- kaline material being made when the temperature of theglycol or polyglycol has reached 60-80 C. When the proportion of glycolor polyglycol to prolamin is less than about three to one by weight, itis preferred to use a closed, jacketed mixer because of the relativelyhigh viscosity of the mixture.

The period of time during which the reaction mixture is heated willdepend upon various factors, such as the particular reactants employedand their relative proportions, the reaction temperature, the propertiesdesired in the final product, etc. The water tolerance usually variesfrom about 40 to about 50% (i. 8;, from about 40 to about 50 gms. ofwater per 100 gms. of reaction mixture at room temperature) when theprolamin first completely dissolves in the glycol or polyglycol toinfinite water tolerance after from one to four hours of heating at 110C. The reaction time required to attain infinite water tolerance issomewhat reduced as the amount of glycol or polyglycol and/or stronglyalkaline material present is increased.

Prolamins which have been modified in accordance with the methoddescribed herein are valuable compositions of matter in that they haveincreased or total miscibility in water, and hence may be used in theproduction of improved printing inks, water-dilutable paints andvarnishes, adhesives, as binders for pigments and fillers in moldingcompositions, as a modifier and extender for synthetic resins such asphenolformaldehyde resins, and for other purposes.

As a specific illustration of the use of the composition of thepresentinvention, a letterpress 4 ink which is very stable on storageand which flash dries rapidly, has good hiding power and prints sharpand clean may be prepared by mixing in the known manner 78 parts of thefinal product of the example, 1 part of milori blue, 20 parts of carbonblack and 1 part or" methyl violet. In addition, pigments other thancarbon black may be incorporated into the composition of the presentinvention to form a printing ink, for example, by mixing 78.8 parts ofthe final product of the example, 10.0 parts of calcium carbonate and11.2 parts of Lithol red.

This application is a division of my copencling application Ser. No.762,211, filed July 19, 1947, now United States Patent No. 2,489,763.

I claim:

1. The method for the modification of a prolamin to increase itsmiscibility with water which comprises heating the prolamin in admixturewith a material selected from the group consisting of glycols andpolyglycols which are infinitely miscible with water at 20 C. and.polyethylene glycols which are not infinitely miscible with water at 20C. but which have a molecular weight below about 1600 and a materialselected from the group consisting of strong alkalis and compounds whichunder the reaction conditions decompose to yield strong alkalis, theheating being conducted at a temperature not in excess of C.

2. The method for the modification of zein to increase its miscibilitywith water which comprises heating the zein in admixture with a materialselected from the group consisting of glycols and polyglycols which areinfinitely miscible with water at 20 C. and polyethylene glycols whichare not infinitely miscible with water at 20 C. but which have amolecular weight below about 1600 and a material selected from the groupconsisting of strong alkalis and compounds which under the reactionconditions decompose to yield strong alkalis, the heating beingconducted at a temperature not in excess of 120 C.

3. The method for the modification of a prolamin to increase itsmiscibility with water which comprises heating the prolamin in admixture with propylene glycol and a material selected from the groupconsisting of strong alkalis and compounds which under the reactioncondition decompose to yield strong alkalis, the heating being conductedat a temperature not in excess of 120 C.

4. The method for the modification of a prolamin to increase itsmiscibility with water which comprises heating the prolamin in admixturewith a material selected from the group consisting of glycols andpolyglycols which are infinitely miscible with water at 20 C. andpolyethylene glycols which are not infinitely miscible with water at 20C. but which have a molecularweigh't below about 1600 and sodiumhydroxide, the heating being conducted at a temperature not in excess of120 C. V

5. The method for the modification of aprolarnin to increase itsmiscibility with water which comprises heating the prolamin in admixturewith a material selected from the group consist ing of glycols andpolyglycols which are innniteiy miscible with water at 20 C. andpolyethylene glycels' which are not infinitely miscible with water at 200., but which havea molecular weight below about 1600 and a materialselected from the grou consisting of strong alkalis and conipounds whichunder the reaction conditions decompose to yield strong alkalis; theheating" be" ing conducted at a temperature within the range of about 80to 120 C.

6. The method for the modification of zein to increase its miscibilitywith water which comprises heating the zein in admixture with propyleneglycol and sodium hydroxide at a temperature within the range of about80 to 120 C.

7. The method for the modification of a prolamin to increase itsmiscibility with water which comprises heating the prolamin in admixturewith a material selected from the group consisting of glycols andpolyglycols which are infinitely miscible with water at 20 C. andpolyethylene No references cited.

1. THE METHOD FOR THE MODIFICATION OF A PROLAMIN TO INCREASE ITSMISCIBILITY WITH WATER WHICH COMPRISES HEATING THE PROLAMIN IN ADMIXTUREWITH A MATERIAL SELECTED FROM THE GROUP CONSISTING OF GLYCOLS ANDPOLYGLYCOLS WHICH ARE INFINITELY MISCIBLE WITH WATER AT 20* C. ANDPOLYETHYLENE GLYCOLS WHICH ARE NOT INFINITELY MISCIBLE WITH WATER AT 20*C. BUT WHICH HAVE A MOLECULAR WEIGHT BELOW ABOUT 1600 AND A MATERIALSELECTED FROM THE GROUP CONSISTING OF STRONG ALKALIS AND COMPOUNDS WHICHUNDER THE REACTION CONDITIONS DECOMPOSE TO YIELD STRONG ALKALIS, THEHEATING BEING CONDUCTED AT A TEMPERATURE NOT IN EXCESS OF 120* C.